Turntable



Nov. 20, 1928. 1,691,948

wHM. VENABLE TURNTABLE Filed May 21 1927 2 Sheets-Sheet 1 m &

avwemtoz Nov. 20, 1928.

'w. M. VENABLE TURNTABLE Filed May 21, 1927 2 Sheets-Sheet 2 awuwnboz Patented Nov. 2-0, 1928.

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WILLIAM MAYO VJ-ENABLE, OF PITTSBURGH, PENNSYLVANIA, ASSIGI'TGR TO BLAVJ- KNOX. COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF NEW JER- suit. 7

Application filed May 21,

constructed in the other half. Under these I conditions, the concrete mixer is located between the road rails, which are only nine feet apart for an eighteen foot roadway, or

eight feet apart for a sixteen foot roadway.

The trucks must approach the mixer in this limited'space, where'ther'e is obviously no maneuvering room to turn them around,- or to operate a turntable constructed to'swing over one road rail only, as in my Patent No.

1,4:46, 228, granted February 20th, 1923.

I aim to provide a turntable that can operate satisfactorily in such a narrow space, even when it is necessary to swing both ends of the table over the road rails. The embodiment of the invention hereinafter described permits a truck approaching the mixer to drive directly upon the table, to be turned around thereon, and to be then backed on the table close enough to the mixer to dump its contents into the charging skip which serves the latter,without backing off the turntable. scribed can be very easily moved or shifted along the roadway, which is particularly advantageous for half width Work; because the mixer must be moved just about twice as often for such work as for laying a road of full width, and the turntable must be moved whenever the mixer is moved, in order to keep it close enough to the mixer to permit the truck to dumpinto the skip as above mentioned. Practically, this means that with trucks of the capacities ordinarily employed on work of this kind, the mixer must be moved after it has disposed of each two truck loads of material. I

However, my invention is also adaptable and applicable to turntables located further off from the mixer, and not moved so frequently.

' In the drawings, Fig. 1 is .a plan view of a turntable conveniently embodying my invention, g

Fig. 2 is a sideview or elevation of'the turntable shownin Fig. 1.

The table'hereinafter de TURNTABLE.

1927. Serial No. 193,121.

Fig. 3 shows a Vertical section through the rotary mounting of the turntable taken as indicated by 33 in Fig. 1, but on a larger scale than Figs. 1 and 2.

Fig. is a fragmentary side view of'the supporting mechanism employed when the table is tobe moved, on a larger scale than" table structure 10 mounted to. turn on a stationary base or sub-frame structure 11 that normally rests on the sub-grade 12. Inthe present instance, the table structure 10 co m pr1ses two separate channel-shaped trackways or driveways13. As shown in Figs. -2 and 3, the t'rackways 13 are elevated to such a height (say about a foot above the subgrade) as to clear and swing overthe road 1 ralls at the sldesof the sub-grade and over I the berm or pavement beyond,as the case may be. To enable a truck to mount the table 10, stationary ramp means may be provided at one or both ends, shown as consisting of a couple of channel ramps 15, 15

(similar to the trackways 13, mounted on the frame structure 11 and permanently secured thereto. 'As the table here shown is intended for trucks to dump therefrom directly into the mixer or its skip,-as described above, only one setof ramps '15 is here shown, To prevent a truck-from running off the turntable 10 when backed up'to tionary stop means 16,- '16 may be provided,

the mixer (not shown) for dumping, stashown as mounted or built on the opposite end of the frame structure 11 from the ramps '15, 15. As shown in Figs. 1 and2, the ends of the channel trackways 13, 13 and of the ramps 15, 15 are cut at such an angle as to enable the table to swing past the ramps and past the stops 16,16 without diificulty, and with suitableclearance.

As shown in Figs. 1, 2 and 3, the base 11 comprises a bottom plate 17 that rests on the ground, and a frame consisting of longitudi-' nal side'members or sills 18, 18 ofchannel section, interconnected by a plurality of transverse beams or 'transoms 19, 19, 20,20, 21, 21, and 22 of channel sectione As shown in Figs. 1 and 3, the side sills 18 and the transoms 19 are located at the longitudinal and transverse edges of the plate 17, and secured thereto. A couple of transoms 20, 20 that rest on top of the side sills 18, 18 are located at the ends of the trackways 13 (when aligned with the'ramps 15, 15), and other transoms 21, 21 a short distance inside the transoms 20, 20. Another transom 22 is lo- "cated at the extreme ends of the side sills 18, 18 beneath the ramps 15, 15, about at their middle. A circular supporting track 23 is rigidly secured to the plate 17, inside the rectangle formed by the members 18, 18,

i 19, 19; which helps to brace and stiffen the is secured to the plate 17. A hollow pivot'boss or hub 24 plate 17 at the centre of the track circle 23. v

The rotary table structure 10 has a circul-ar inverted track 25 (conveniently distinguished as a turning track) secured to the bottoms of the trackways 13, for cooperating with the base track 23, and also a transverse inverted channel member 26 interconnecting the trackways 13, 13 across the centre of the trackcircle 25. This member 26 and the turning track 25 serve as a stifl'en ing frame-work for securing the trackways 13, 13 together and bracing them with reference to one another. The transverse memher 26 carries apivot hub or plate 27, secured to its lower side at the centre of the track circle 25. The table 10 is centered on the base 11 by a vertical pivot pin or stud 28 engaged inclined plates each supported by a couple of vertical web plates 37, 37 secured to the inner in the base hub 24 and in the table hub 27 The frictional resistance ofturning the table 10 may be minimized by a multiplicity of anti-friction rollers 30 interposed be-.

tween the base and table tracks 23 and 25.

I As shown, these'frollers 30 are mounted on.

7 secured to the transverse member 20 and to angle clips 34, 34 attached to upright web plates 35, 35 whose bent ends are secured to the side sills 18, 18and to short longitudinal members 36, 36 interconnecting the members 20 and 21. V Thesupports 33, 33 project beyond the ends of the ramps 15, 15 to support.

the corresponding ends of, the trackways 13, The stops 16, 16am shown as transverse sides of the longitudinal sills 18, 18 and to longitudinal members 38,38 similar to the members 36, 36., There are also supports 39,

39 for the corresponding ends of the track ways 13, 13, similar to the supports 33, 33

and similarly mounted on the frame structure 11,-as indicated by the use of like reference numerals applied tothe parts involved.

While the frame structure 11 rests ,dircctly on the ground throughout. its length when the table is in operation, provision is preferably made for less frictional support of the table when it is to be moved'or shifted.

For this purpose, the frame 1 1 is shown pro vided with ground wheels or rolls 40 located approximately at its corners, and shiftable down and up into and out of supporting cont-act with the ground. As shown in Figs. 1, 2, 4 and 5, each of the wheels 40 is mounted on a short axle 41 in a yoke 42 fast on a. shaft 43 in bearings 44, 44 seeuredto the longitudinal members 18 and 36 at one end or 18 and 38 at the other end; Each shaft 43 extends out through the web of the side sil-l'18, and may be turned throughan angle of 90 orthereabout by means ofa hand lever 45 on-its outer end,-s as'to swin-g the 'wheel yoke 42 downwardly with the wheel 40von the ground and supporting the table entirely, as in Fig. 2, or upwardly with the wheel 40 above the plane of the bottomof the frame structure 11, as shown in Figs. 1, 4 and 5. .In this latter condition, the structure 11 rests directly on the ground. I

As here shown, the hand lever 45 for each wheel 40 is not fast to the shaft 43, but" releasably connected to it, so that, said lever may not only lie out ofthe'way alongside the sill 18 when the wheel 40 is in ground'engaging position, as in Fig. 2, but

also when the wheel is raised as inFig. 4.

For this purpose, ratchet. tooth and pawl mechanism may ,beiemployed, such as a ratchet tooth .member 46 keyed fast to the end of the shaft 43, and a pawl 47 pivoted.

to the lever 45 at 48, between the lever itself and a bracket 49 secured thereto.- gagement of the pawl 47 -with the member 46 may be controlled by a handle 50,- pivoted to the hand lever near-its free end and con- -nected to the pawl 47 by a link rod 51'.

\Vhen the hand lever 45 is not in use, it may be held against the sill 18 by engaging it behind a hook device 52z'secured to the sill:

.when it is to beused, it is pressed down to The en- Ill!) release it from this'hook' 52 and their sprung out sidewisea little until swung up clear-of the book When the pawl 47 is engaged with the member 46, the hook 52 serves as a means of locking the wheels 40 and their mountings 42 in grounchengaging position, as in Fig.2.

In service, a truck, approaching the mixer (not shown) drives up the ramps 15 upon the trackways 13,-the supports 33 sustaining the corresponding tradkwayends against tipping down under the as yet unbalanced truck. Thetruck is driven on the" table until its center of gravity lies inside the supporting and turning track circles 23', 25, so that it is at least approximately balanced on the table. In this condition,

both of the tracks 23, 25' are in contact with all of the rollers. 30, and the trackways 13,

13 are evenly balanced, as shown in Fig. 2, with their ends automatically disengaged and clear of the supports 33, 39, the trackways 13,- 13 being stiff enough to carry the weight of the vehicle without material deflection.

The table 10 then turned end for end,

' 23, so that it is unbalanced on the table,

and the corresponding ends of the trackways 13, 13 rest on the supports 39, 39L The truck may then be dumped, in the usual manner, into the mixer charging hopper (not shown) located beyond the stops 16, 1G. The empty truck is then driven forward down the ramps 15, 15 and oil the turntable, in the direction whence it approached.

In Fig. 2, the ground wheels 40 are shown in the position which they occupy when the turntable is to be moved, with the frame 11- clear of the sub-grade 12. 40 in this position, the table can easily be moved by the mixer itself, which can push against the corresponding transom 20, and thus push the turntable along before it. When the table has been brought to the desired new position, the levers are released from the Catches 52, as already described, and allowed to rise, thus allowing the wheel mounting shafts 43 to turn and thetrame 11 to sink down and rest upon the subgrade 12. Thereupon, the pawls 47 may be released from the ratchet teeth 46 and the levers 45 returned to their position shown in Figs. 2 and 4.

In practice, the four levers 45 may be successively operated (either to lift the table on the wheels 40, or to lower it) by a single workman, or both levers 45, 45 at one end of the table may be simultaneously operated by two men stationed at opposite sides of the table, and then the levers 45, 45 at the other end may be similarly operated. Usually, a couple of the men employed about the mixer or in spreading concrete will be conveniently available to do this at the time the turntable is to be moved.

The arrangement for relieving the wheels 40 of the weight of the table when it is in operation obviates the necessity of making its framing 11 so very strong as to stand the weight of a truck on the table when the 'frame is supported only by the wheels 40,

and also obviates sinking of the wheels into the sub-grade 12 under the weight of the truck. In other words, the wheels 40never have to carry the weight of both turntable and truck, but only that of the unloaded turntable.

vVith the wheels 1. A roadway turntable comprising a-base structure with ramps adapted to rest directly on theground, atable structurerotat ably mounted thereon, four ground wheels for said base structure swingable up and down relative thereto, into and out oi grounds engaging position, and hand lever mechanism for shifting said ground wheels aforesaid. I I

2. A roadway turntable comprising a base structure adapted to rest directly on the ground, a table structure rotatably mounted thereon, tour ground Wheels for said base structure with mountings swingable up and down relative thereto, into and out of ground-engaging position, and ground-wheel shitting means including a hand lever swingable up and down and ratchet mechanism for operatively connecting the same to a ground wheel mounting and disconnecting it therefrom.

3. A roadway turntable comprising ramps rigidly secured to a base structure adapted to rest directly on the ground, a table structure rotatably mounted on said base structure, ground wheels for both sides of said base structure shiftable up and down into ground wheels for the two ends of said base structure.

5. A roadway turntable comprising'a base structure adapted to rest directly on the ground, a table structure rotatably mounted thereon, ground wheels for the corners of said base structure shiftable up and downinto and out of ground-engaging position, and means for shifting said wheels as aforesaid independently of one another.

6. A roadway turntable comprising a base structure, with side sills, adapted to rest directly on the ground; a table structure rotatably mounted thereon; ground wheels for said base structure swingable up and down inside said side sills, into and out of ground-engaging position; and hand levers for shifting said ground wheels swingable up and down outside said side sills.

7. A roadway turntable oomprisinga base structure, with side sills, adapted torrest directly on the ground; a table structure rotatably mounted thereon; ground wheels for said base structure with mountings piv-- oted to swing up and down inside said side sills,' into and out of ground-engaging position; and ground Wheel shifting means cornprising hand levers swi'ngableup and down outside said side sills andratchet mechanism for operatively connecting the hand levers to the ground Wheel mountings and discon ground, a table structure rotatably mounted thereon, a ground Wheel at each corner "of the base structure swingableup and down relative thereto into and out of ground engaging position, and hand lever mechanism for shifting said ground Wheels as aforesaid. w In testimony whereof I have hereunto signed my name.

WILLIAM- MAYOVENABLE. I 3 

